One I had, in the 80s (North Star, Ealing if anyone know's it) was most memorable. I'd only gone in for a couple of pints (I think it opened quite early) and saw they were doing a roast lunch (notionally Christmas, I suppose) and thought, sod it, why not. 4, maybe 5, pints later I made my way to West Ealing (Drayton Arms) to join others for the planned eat and drink.
It sounds kinda lonely I suppose but then I was a single bloke with no family (in London) and spent a number of Christmas Days in pubs with friends. That one particularly stands out though. It was remarkably chill; quiet pints, roast lunch and a bit of a chat with similarly sing!e folk (predominantly blokes) It was another side of Christmas and I enjoyed if for that.